Patient's glasses: 1) spherical 6 Base 1) aspherical 3 Base - has issues with one ???

[William Walker]

I have a patient who recently received a poly spherical 6 base lens from a competitor.

He came and ordered a backup pair from us (same Rx). Our poly is aspheric, and the base curve is a 3.

He's having issues seeing swim and distortion in the periphery through our lens. It's a SV. I've checked everything I could think of (power in the new set and the old, PDs and OCs in both sets) to look for anomalies, but the only thing I can find that's different is the base. If I recall correctly, when using an aspheric lens, the curve is 3 less than the spherical curve.

The patient is wearing them for a few days while I'm out of the office, and I want to followup with him when I return. If these don't work, our only option is a CR-39 (which is spherical and available on a 6 base), or a refund.

According to the textbooks, I don't think he should be having this problem - should he?

Thanks,
William

[braheem24]

put the poor guy in a 6 base non aspheric 1.6, surfaced poly or cr-39 and he'll be fine. The asphericity is in the periphery which is also his complaint either get him one of the above or fit him in a smaller frame that will cut out the aspheric portion of the lens.

[jpways]

Three questions:
1. What is the patient's total power
2. Is the wrap the same between the new glasses and the old glasses?
3. If the wrap is the same are the two thickest edges the same distance from the eye?

The reason for my questions are under the premise that the patient is a moderate to high myope, under this case the higher the power, the higher the peripheral distortion. One way to minimize the affects of this distortion is to add wrap, thus pulling the area of distortion out of the patients line of sight. With the steeper (standard poly) lens I would expect the thickest edge to be closer to the patient's face then the flatter (aspheric poly lens), given a constant frame wrap, thus bringing the area of distortion into the line of sight of your patient. Thus, you have to increase the wrap on your job to match the position of the lens on your competitor's job (thickest edge to thickest edge).

Another alternative if wrap isn't the answer and if the lens costs are similar enough that this is a cost effective solution, would be to switch the patient to an aspheric/atoric (aka double aspheric) lens, like the Resolution, you would hopefully minimize the peripheral distortion sufficiently so that the patient could use the lenses without affecting the wrap of the frame to the point that the patient may no longer like the fit

[sharpstick777]

Its a huge difference in BC between 6 and 3. Without the RX its impossible to know which is best. I have had patients get used to the wrong BC had a nightmare when they switched. People just get used to what they have.

Stay with aspheric... but he may have to wear them solid for a while. Also, which aspherics did you use? Some aspheric designs are optimized for cosmetics, some for vision. You may need to put him another brand aspheric (I would try Seiko). Not all aspherics are the same.

[Happylady]

Why not switch him to a non aspheric poly on a 6 base?

[William Walker]

Thanks for the suggestions. My only options are a spherical CR-39, aspheric poly, or aspheric 1.67.

I realize there's a big difference between a 6 base and a 3, but there's also a corresponding difference between a spherical and aspheric lens.

I'll get the script when I go back to work Wednesday, but I remember also checking the face wrap of the frames, and setting the glasses on top of each other, the frames looked identical in wrap.